The anti-depressant, brain fog, and histamine intolerance connection, is another poorly understood area.

Drug intolerances are extremely common with histamine intolerance yet there is still much that is not known. Does histamine intolerance result in drug intolerance, or do drug intolerances trigger histamine intolerance in some people? We simply do not know.

Beyond that there is still much work to be done. In the absence of clinical trials, we are left with clinical observations of medical professionals, working on the cutting edge in clinical practice.

This post looks at the medical hypothesis of Professor David Healy, a psychiatrist, and psycho-pharmacologist, with an active interest in adverse drug reactions to psychotropic drugs. Here are some of his interesting clinical observations relevant to histamine intolerance:

A new study by Maintz and Novak et al concludes that the histamine intolerance and diamine oxidase connection alone does not explain histamine intolerance (HIT). Previously, genetic mutations in DAO, were hypothesised to be the sole cause.

Histamine Intolerance

HIT is the result of an imbalance between histamine and the capacity for histamine…

The intestinal mucosa is a protective layer in the gut that contains a wide range of enzymes used in digestion and nutrient absorption. One of these enzymes is DAO.

DAO protects the body against an excessive buildup of histamines by degrading both ingested and bacterial histamine.

The amount of DAO synthesised can be reduced due to a genetic mutation (DAO deficiency) but it is nutrients which make it bio-available. This means that what we eat will determine whether available DAO is transported into the gut and bloodstream.

This is not speculation. A study examined each of the key nutrients and here is what they found: